From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.5 required=3.0 tests=BAYES_00, DKIM_ADSP_CUSTOM_MED,DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 34E01C43460 for ; Tue, 18 May 2021 20:08:33 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id DFCDB6108D for ; Tue, 18 May 2021 20:08:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DFCDB6108D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 7D70A8E004C; Tue, 18 May 2021 16:08:32 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7AF568E002F; Tue, 18 May 2021 16:08:32 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6532F8E004C; Tue, 18 May 2021 16:08:32 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0227.hostedemail.com [216.40.44.227]) by kanga.kvack.org (Postfix) with ESMTP id 244308E002F for ; Tue, 18 May 2021 16:08:32 -0400 (EDT) Received: from smtpin27.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id B14308249980 for ; Tue, 18 May 2021 20:08:31 +0000 (UTC) X-FDA: 78155439222.27.04A2873 Received: from mail-pl1-f179.google.com (mail-pl1-f179.google.com [209.85.214.179]) by imf02.hostedemail.com (Postfix) with ESMTP id 1FFA44080F55 for ; Tue, 18 May 2021 20:08:28 +0000 (UTC) Received: by mail-pl1-f179.google.com with SMTP id t4so5735618plc.6 for ; Tue, 18 May 2021 13:08:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=Bft5/S3sIep+UIOe0wjEBCs4qeqthplQvAas8/8e+yo=; b=nHLS3OJzElgnE2B/Z8SKCricVXLIx3iJxQjJ0syYMD0st4Cu/HagKgnXREM54zswjw XMNbtKvBMaoANopTaCd8U7u2Hm86+M3RuZtminAUpNjSsKZa0ANHy7i82oYV5IUBo3y5 9as9AvR0a6Tf/pms+EH7p0fkg0BSIgxX0pHVwN8P5Wx2tzfzJWe1qn5USVLiIJCq+FuE BSJupLShAnX1rbhtkb46N4UqYZ8EQt19Oxj+xOEtlDuZCPe1a2dfSKZZsE6riRl+RTUN VZadMbE778WhVEQIFJBh5I6kdzgTgYVgZZeinQpMkA7oXwHQKhc9R+s52vZyIwRN3/vc 4HjQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=Bft5/S3sIep+UIOe0wjEBCs4qeqthplQvAas8/8e+yo=; b=fLbtqtFlCmDFJ4mwcaUeBeBA7ZCbdfd4ES2I6hkqjBa/Unb9V6EU24xRknyGM1c9Rz CeizyIYHM2UVZIIAwT32w80nS2HEoQLwGVN/LN2codncQSXb7e0jxgxB8yLFdvor1RoX rHL8gqOWruIE7kWeuFD109grbzuZ8pEjfpFcK3HF3Glmim1OmR8nrJ5NcXL745Tjqfw+ 7OC0IFJCHb7yHXniBsaHPmhZKgMDuBaqLi2zobWZMXbDBRI1RFprLLhklUImjHsPGAse n0QKEscWZbjj0pjSUWkaXaOYSi4Hr5q57ZugScr9FCud/r33bXE1ubIOB0mG95K8QvQG j3ww== X-Gm-Message-State: AOAM530wynkR/sQMNMQW4PNr6BfftG+Hv+pc+VQq9vjgNbkbeYTMOcWi UYKF58AcoDPy9+zCbhZo/zw= X-Google-Smtp-Source: ABdhPJycucOy8RWBt3ZSLaK0DULZYOHapGP8SDJZBX29cfFbM7ELURa2SaI9yfmt82bS4uEWVqBwiA== X-Received: by 2002:a17:902:e007:b029:ef:9dd2:be6 with SMTP id o7-20020a170902e007b02900ef9dd20be6mr6495035plo.12.1621368510709; Tue, 18 May 2021 13:08:30 -0700 (PDT) Received: from localhost.localdomain (c-73-93-239-127.hsd1.ca.comcast.net. [73.93.239.127]) by smtp.gmail.com with ESMTPSA id r11sm13456600pgl.34.2021.05.18.13.08.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 18 May 2021 13:08:29 -0700 (PDT) From: Yang Shi To: mgorman@suse.de, kirill.shutemov@linux.intel.com, ziy@nvidia.com, ying.huang@intel.com, mhocko@suse.com, hughd@google.com, gerald.schaefer@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com, borntraeger@de.ibm.com, akpm@linux-foundation.org Cc: shy828301@gmail.com, linux-mm@kvack.org, linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [v3 PATCH 6/7] mm: migrate: check mapcount for THP instead of refcount Date: Tue, 18 May 2021 13:08:00 -0700 Message-Id: <20210518200801.7413-7-shy828301@gmail.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20210518200801.7413-1-shy828301@gmail.com> References: <20210518200801.7413-1-shy828301@gmail.com> MIME-Version: 1.0 X-Rspamd-Queue-Id: 1FFA44080F55 Authentication-Results: imf02.hostedemail.com; dkim=pass header.d=gmail.com header.s=20161025 header.b=nHLS3OJz; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf02.hostedemail.com: domain of shy828301@gmail.com designates 209.85.214.179 as permitted sender) smtp.mailfrom=shy828301@gmail.com X-Rspamd-Server: rspam03 X-Stat-Signature: o5mdnzr654pn7cwurb8hcefiswx85p5r X-HE-Tag: 1621368508-542250 Content-Transfer-Encoding: quoted-printable X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: The generic migration path will check refcount, so no need check refcount= here. But the old code actually prevents from migrating shared THP (mapped by m= ultiple processes), so bail out early if mapcount is > 1 to keep the behavior. Signed-off-by: Yang Shi --- mm/migrate.c | 16 ++++------------ 1 file changed, 4 insertions(+), 12 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index 035daaec1ca0..77215f28502b 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2070,6 +2070,10 @@ static int numamigrate_isolate_page(pg_data_t *pgd= at, struct page *page) =20 VM_BUG_ON_PAGE(compound_order(page) && !PageTransHuge(page), page); =20 + /* Do not migrate THP mapped by multiple processes */ + if (PageTransHuge(page) && total_mapcount(page) > 1) + return 0; + /* Avoid migrating to a node that is nearly full */ if (!migrate_balanced_pgdat(pgdat, compound_nr(page))) return 0; @@ -2077,18 +2081,6 @@ static int numamigrate_isolate_page(pg_data_t *pgd= at, struct page *page) if (isolate_lru_page(page)) return 0; =20 - /* - * migrate_misplaced_transhuge_page() skips page migration's usual - * check on page_count(), so we must do it here, now that the page - * has been isolated: a GUP pin, or any other pin, prevents migration. - * The expected page count is 3: 1 for page's mapcount and 1 for the - * caller's pin and 1 for the reference taken by isolate_lru_page(). - */ - if (PageTransHuge(page) && page_count(page) !=3D 3) { - putback_lru_page(page); - return 0; - } - page_lru =3D page_is_file_lru(page); mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON + page_lru, thp_nr_pages(page)); --=20 2.26.2